The gaseous volatile organic compounds (VOCs) sensors with high-selectivity and low-power consumption have been expected for practical applications in environmental monitoring and disease diagnosis. Herein, we demonstrate a room-temperature VOCs gas sensor with enhanced performance based on TiCT-TiO nanocomposites. The TiCT-TiO nanocomposites with regular morphology are successfully synthesized via a facile one-step hydrothermal synthesis strategy by using TiCT itself as titanium source. Attributed to the formation of interfacial heterojunctions and the modulation of carrier density, the TiCT-TiO sensor exhibits about 1.5-12.6 times enhanced responses for the detection of various VOCs at room temperature than pure MXene sensor. Moreover, the nanocomposite sensor has better response to hexanal, both an air pollutant and a typical lung cancer biomarker. The gas response of the TiCT-TiO sensor towards 10 ppm hexanal is about 3.4%. The hexanal gas sensing results display that the nanocomposite sensor maintains a high signal-to-noise ratio and the lower detection limit to hexanal gas is as low as 217 ppb. Due to the low power consumption and easy fabrication process, the TiCT-TiO nanocomposite sensor is promising for application in IoT environmental monitoring as well as real-time health monitoring.